Phonograph pick-up device



0%. 8, 1931. I s, McCLATcl-"E 1 1,835,073

PHONOGRAPH PICK-UP DEVICE Filed Deq. 5, 1929 2 Sheets-Sheet 1 IIIIII Ill III

HTTORHEY Dec. 8, 1931. s. M CLATCHIE PHONOGRAPH PICK-UP DEVICE Filed Dec. 5, 1929 2 Sheets-Sheet 2 INVEHTOR BY Stanley ML'CVRTC/IIGT HT ORNEY ing drawings,

tion will be particularly pointed out in the ap- Patented Dec. 8, 1931 UNITED STATES P ATENT" -orrlcs i V McGL Arc'nrn, or nn'nmn-w'inivrsnsnonr, GERMANY PHONOGRAPH PICK-UP nnvrcn Application filed December 5, 1929,

Thisvinvention relates to sound reproducing devices and is more particularly concerned with sound pick-up devices for electro-magnetic reproduction of sound or speech recorded upon a phonograph record.

Among the obyects of-the invention are to provide increased faithfulness of reproduc tion to reduce the cost of manufacture, to simplify the changing of needles,and to increase the lifeof needles and records.

Thevarious features and objects of the reference tothe following detailed description taken in'connection with the accompanywhile the scope of thelnven pended claims.

In the drawings; Figure 1 is a lon 'tudinal section through my invention. Figure 2 1s a side elevation of the sound box shown in Figure land illustrates its po-' sition with'respect to the record, Figure 3 is ELSGCtlOIlZLl view along the sectionline A-B of F1gure1. i

F igure 4 shows,.on an enlarged scale, a

fragmentary longitudinal section through the sound box illustrated in Figure 1, the

omitted from the view. Figure 5 is a longitudinal section through a modified form of soundzbox, in which the needle itself serves as the armature.

Figure 6 is a chamber magazine is attached to the ,sound box for holding a large number of needles.

Figure 7 is a longitudinal section through Serial No. 411,86 1,and in Germany 7 tube or sleeveof magnetic material provided I invention will be more fully understoodupon holder, which results in a needle sectional view, partly 111 elevation, of a further modification, in which, a

in Figures lto 4", the sound box casing l has mounted therein a U-shaped permanent magnet 2 and pole pieces 8. v The pole pieces may be made of sheet metal plates held in place by means of screws or, rivets (not shown) Mounted between the pole pieces is a spool 4 upon which, is wound a 0011 5 (see Figure (l) Concentrically arranged with respect to the coil 5 isan armature 6 comprising a metal with a slot 7 which holds a needle 8 by resilient-clamping action exerted on the needle, The armature 6 is-flanged at its lower end, as 1 shown in Figure 4, for the purpose of allow- The I ing'easy insertion of a needle therein.

flange issurrounded by a soft gasket 9 to excludedirt and iron particles from the pole. pieces. Surrounding the armature, 1 is a cylindrical member 10 of elastic material whiclrforms acushioning mass or damping 0 means for damping the oscillationsof the armature." This construction eliminates the necessity for a clamping screw and screwlarge reduction in the Weight of the oscillating mass.

The permanent magnet 2 is supported in, the casing 1 by means of a tubular member 11 which extends throughan opening in the casing. In engagement with the outer end of the tubular member is a'knob 12. This construction provides a means for controlling the volume of the sound. To adjust thevolume the knob 12 is turned, thereby turning the magnet l with respect to the pole pieces 3. ring 13, preferably of'felt, is inserted between the magnet and the casing, in order to press the magnet lightly against the pole pieces,

Extending through the tubular member 11 isa second tubular member 14:, the inner bore of which is of a diameter just sufficient to receive the needles to be used; The member 1 1 is arranged in alinement with the armature 6 and has its lower end flared and terminatingjustabove the pole pieces'3. The tubular member 14 serves as a magazine for I spare needles, To'effect'replacement of the needle 8 a'spare needle is introduced into the upper end of the member let and pusheddown' 7 until the needle 8 is expelled. i i:

In the form of the invention illustrated inmature Figure 5 the armature 6 is omitted and the needle itself serves as the armature. In place of the tubular member 14 a member 15, of somewhat different construction, is employed and a rod 16 extends through this member for the purpose of forcing a used needle out. A spring 17 is provided for re turning the rod 16 to the position shown in Figure 5.

In the embodiment illustrated in Figures 6, 7 and 10, a chamber magazine 18 is provided for storing a large number of needles.

spring 19 arranged between one end wall of magazine 18 and a movable intermediate wall 20 exerts pressure against the wall 20 to retain the needles in proper position. To fill the magazine 18 the wall 20 is pushed back by means of a knob 21 operating in a guide slot 22 against the action of the spring 19 and the needles are inserted through the opening 23 provided in the upper wall of the magazine. For the purpose of bringing a new needle into play, there is provided an element 24 having a knob 25 operating in a guide slot 26. In this form of the invention adjustment of the magnet with respect to the pole pieces may be effected by a lengtlrwise displacement of the magnet as by means of a screw 27 i In the embodiment illustrated in Figure 8 the pole'pieces consist of four sheet metal plates 28, the two upper plates being sepa rated from the two lower plates by a spacing member 29. Iron screws 30 extending through holes in the spacing member 29 secure the upper and lower plates together and complete the magnetic circuits. In this form of the invention prises gaskets 31 pieces and the spool. Also, a resilient ring 32 is provided surrounding the armature 6, for the purpose of increasing its clamping action and insuring a tight hold of the phonograph needle. The holes provided in the spacing member 29 for the reception of the screws 30 are made somewhat larger than the diameter of the screws, so that the pole pieces may be adjusted with respect to the armature.

By reducing the armature to a mere tube of thin material immediately surrounding the needle, the oscillating mass is kept extraordinarily small. The usual weight of the ar- (about 5 grams) about 0.2 gram, whereby the damping factor, which depends essentially on the armature weight, is decreased correspondingly. Thus, theresonance peak is kept low without the use of so much damping as has heretofore been necessary. This reduced damping leaves the armature very free to respond to oscillations of low frequency and relatively large amplitude. It is, therefore, not necessary as heretofore to make the pick-up as a whole quite heavy. in order to prevent the may be decreased to" same from oscillating with the needle at the lower frequencies.

The improved construction has, therefore, the further effect of preserving the records as well as the needles to a considerable extent. On account of the small mass and damping of the mechanically oscillating parts, the frictional forces are so small that the life of the record and the needles is increased several times. l Vith the increased life of the records and needles, it is no longer necessary, as heretofore, to change a needle after completion of a single record.

By providing for the regulation of the volume of sound by varying the position of the magnet with respect to the pole pieces, a further decrease in the cost of the sound box is'obtained as this eliminates the necessity for the use of a special sound regulator such as a potentiometer. Finally, the replacement of a needle is made extremely easy.

While I have herein described my invention more or less specifically with reference to the drawings, it is to be understood that various modifications may be made without departing from the spirit and scope thereof, in at taining the objects hereinbefore set forth.

WVhat I claim as new and desire to secure by Letters Patent of the United States is:

In a magnetic sound-reproducing device for phon ographs and the like, a casing, a magnet supported thereby, pole pieces for said magnet, a sleeve of magnetic material positioned between said pole pieces to serve as an armature for said magnet, a needle to be subjected to mechanical oscillations held within said sleeve, and a supporting member of yielding material surrounding said sleeve and damping the oscillations of the same.

In a magnetic sound-reproducing device for phonographs and the like, a casing, amagnet supported thereby, pole pieces for said magnet, a sleeve of magnetic material positioned between said pole pieces, a needle to be subjected to mechanical oscillations held within said sleeve, and a damping support for said sleeve, a magazine chamber for receiving spare needles associated with said casing and means for expelling said needle from said sleeve and replacing it by one of said spare needles.

3. In a magnetic sound-reproducing device for phonographs and the like, a casing, a magnet supported thereby, pole pieces for said magnet, a tubular cushion arranged between said pole pieces, a resilient slotted sleeve of magnetic material positioned within said tubular cushion and serving as the said pick-up device, a needle to oscillations held within said whereby said cushion is adapted to support said needle in operative position and dampen the mechanical oscillations thereof, a magazine chamber for receiving spare needles associated with said casing pole pieces for said magnet, an armature associated with said pole pieces to be subjected to mechanical oscillations corresponding to oscillations of sound to be reproduced and means for gradually adjusting said magnet angularly with respect to said pol-e pieces during operation. 1

6. In a magnetic sound-reproducing device for phonographs and the like, a magnet, pole pieces for said magnet, an armature arranged between-said pole pieces to be subjected to mechanical oscillationscorresponding to oscillations of sound to be reproduced, and rotatable means for gradually adjusting said magnet from and towards said pole pieces during operation.

7. In a magnetic sound-reproducing device for phonographs and the like, a casing, a magnet supported thereby, pole'pieces for said magnet, a tubular cushion arranged between said pole pieces, a needle to be subjected to mechanical oscillations arranged within I said cushion and means to control the position of the magnet'with respect to its pole pieces during operation.

8. In a magnetic sound reproducing device for phonographs andthe like, a casing, a magnet supported thereby, pole pieces for said magnet, an elastic tube arranged between said pole pieces, a sleeve of resilient material surrounding said elastictube, a needle to be subjected to mechanical oscillations, supported within said resilient sleeve, and means to control the position of said magnet with respect to its pole pieces.

9. In a magnetic sound-reproducing device for phonographs and the like, a casing, a magnet supported thereby, pole pieces for said magnet, an armatureto be subjected to up device, a tubular cushioning element surrounding said sleeve for damping the vibrations thereof and for maintaining the needle in operative position, and means to control the position of said magnet with respect to its pole pieces.

In testimony whereof I aflix my signature.

STANLEY MoCLATOI-IIE.

mechanical oscillations arranged between said pole pieces, a single element of yielding material for holding said needle in operative position and for damping vibrations thereof,

and means to gradually control the angular position of said magnet with respect to said pole pieces during'operation.

10. In a magnetic sound-reproducing device for phonographs and the like, a casing, a magnet attached to said casing, pole pieces for said magnet, a resilient slotted sleeve of magnetic material holding a phonograph needle and forming the armature of said pick- 

